In magnetic disc drive storage devices, digital data are written to and read from a thin layer of magnetizable material on surfaces of one or more rotating discs. Read and write operations are performed through read and write transducers that are carried on a slider body. The slider and transducers are sometimes collectively referred to as a head, and typically a single head is associated with each disc surface. Air is dragged by the disc due to rotation of the disc, generating a generally circular airflow pattern around the disc axis. Each slider body includes an air bearing surface (ABS) that reacts with the air dragged beneath the ABS due to rotation of the disc. The air flow develops a lifting force to lift and “fly” the head above the disc surface.
The slider body is mounted to an actuator arm that is rotated about an axis distal from the disc axis. As the actuator arm rotates about its axis, the slider body is moved along an arcuate path that is generally radial across the disc, to thereby confront selected concentric recording tracks on the disc. Due to the arcuate path of the slider relative to the disc, the skew of the slider relative to the circular tracks on the disc changes as the slider is moved radially across the disc. More particularly, the skew changes between a positive and negative skew as the slider is moved between outer and inner radial tracks. Since the airflow confronting the slider is generally tangential to the track, the changing skew of the slider alters the slider orientation relative to the airflow direction as the slider is moved between the outer and inner tracks. Consequently, the airflow impinges the leading edge of the slider and one or the other side of the slider as the slider is radially moved relative to the disc.
The objectives of most disc drive technology advances are directed to increasing areal density of data recorded on magnetic media and to increasing accuracy of recording and recovering of data. These objectives often require lower fly heights of the slider and transducer to the recording media. To achieve these objectives, a class of sliders has been developed known as proximity advanced air bearing (AAB) sliders. AAB sliders are characterized by employing air bearing surfaces (ABS) that are contoured to achieve desired fly characteristics. The air bearing surface of the AAB slider usually includes stepped regions that permit the air to pass beneath the ABS. Without these steps, the ABS may be too close to the disc to permit air to enter the region between the disc and the slider. The stepped ABS admits air into the region beneath the slider, thereby creating the hydrodynamic lifting force to lift the slider and fly it above the disc surface.
One problem of sliders is that particulate matter (particles and debris) may accumulate on the slider and on the transducer. The accumulated particulate matter may adversely affect the flying characteristics of the slider, and may adversely affect the transducing properties of the transducers. Moreover, if the accumulation of particulate matter becomes too great, the slider may drag the particulate matter against the media surface, thereby damaging the slider, transducer and/or disc. In any case, damage may occur, resulting in a loss of data, and in worst cases a failure of the disc drive. Particulate matter is particularly adverse to AAB sliders due to their low flying characteristics. Moreover, the step level features at the leading edges of the ABS of AAB sliders usually direct airflow toward the trailing edges of the slider. The airflow carries particulate matter, which accumulates on the transducer at the trailing edge, leading to head failure.
To reduce accumulation of particulate matter and thereby improve particle insensitivity performance, some AAB sliders are designed to block particles from entering the region beneath the slider. One technique is to employ an ABS that extends across the leading edge of the slider, thereby effectively blocking the particles from entering the region beneath the slider. However, the low flying ABS also blocks airflow, thereby reducing pressurization of the air bearing surface and adversely affecting flying characteristics of the head. Consequently, it has been proposed to include a groove or channel in the ABS across the width of the slider at, or immediately following, the leading edge. The concept of the groove, which could be at either the ABS step level or the slider negative pressure cavity level, was to improve the AAB performance and also to accumulate particulate matter entering the region beneath the slider in the groove. However, when the slider was in a skew orientation such that airflow was from one side of the slider or the other, the groove formed an air channel that directed air from the windward side of the slider toward the leeward side. The airflow carried particulate matter in the groove toward the trailing edge of the slider and the transducer. Consequently, air and particulate flow toward the trailing edge was promoted by the groove, thereby increasing accumulation of particulate matter at the transducer and the trailing edge of the slider.
The present invention provides a solution to this and other problems, and offers other advantages over the prior art.